CHICAGO (CBS/AP) -- Bands of ice, sleet and rain were upending some holiday travel plans as millions of Americans took to the roads, skies and rails Wednesday for Thanksgiving, but the wintry mix was not causing the widespread gridlock that had been feared.

So far, the storms barreling over the mid-Atlantic and Northeast have not sent widespread flight delays or cancellations rippling beyond the region to other parts of the nation's air network, and forecasters said the storm would start to loosen its grip on the East Coast as the day wore on.

"Yes, I'm worried," said Sylvia Faban, an 18-year-old college freshman waiting to launch into the heart of the wintry mess in New York from Chicago, where skies were a clear crystal blue. She and a few travel buddies could do little more than slump down on top of their bags at O'Hare International Airport and wait.

"I'm checking the weather in New York," she said as her fingers pecked at her smartphone.

CBS News correspondent Terrell Brown reported on "CBS This Morning" Wednesday that more than 5,400 flight delays were reported across the country Tuesday and airlines were hoping that doesn't cause a ripple effect, especially with airports out west.

Forecasters say up to a foot of snow could come down in areas near Lake Ontario and Lake Erie. Reporter Heather Abraham of CBS Pittsburgh station KDKA-TV reported on "CBS This Morning" from New Castle, Pa., about an hour north of Pittsburgh, that about 6 to 8 inches of snow has fallen there since Tuesday.

Further north, in western New York, forecasters predict that snowfall totals could reach double digits, Abraham reports. A strong snow system blanketed Buffalo overnight. Some flights out of Buffalo Niagara International Airport were already canceled, and a winter storm warning was in effect there until late Wednesday.

By midday Wednesday, around 250 flights to, from or within the United States had been canceled, according to the air tracking website FlightAware.com. Most of the scrapped flights were in or out of three major Northeast hubs: Newark Liberty International, Philadelphia International and LaGuardia.

According to FlightAware data, 169 flights were canceled Tuesday. A total of 1,584 flights have been canceled this week, including 789 on Sunday and 429 on Monday. Since 7 a.m. Wednesday, more than 300 flights have been delayed.

Some of the longest delays were affecting Philadelphia-bound flights, which were being held up at their points of origin for an average of about two hours because of the weather, according to the website. The Philadelphia area was under a flood watch with 2-3 inches of rain forecast to fall before colder temperatures turn precipitation to snow.

Roads there were snarled. A multi-vehicle crash closed the westbound lanes of the Schuylkill Expressway - Interstate 76 - in the Philadelphia area after eastbound lanes were closed due to flooding on what is traditionally the year's busiest travel day. One lane was later reopened in both directions.

Most of the country was spared by the weather, and many travelers were pre-occupied by nothing more than whether they'd make a tight connection. Travelers at O'Hare were even surprised by how quiet and orderly it was.

Others, like Pat Wilson in suburban Detroit, were just excited to set off on a new journey.

She and her immediate family have never ventured from home before for Thanksgiving, but decided to get on an Amtrak train from Dearborn to Chicago after her 9-year-old granddaughter said she really wanted to go there.

"She requested it," said Wilson, 65, adding that the visit will almost certainly include a stop at the city's American Girl store, a mecca for girls who are fans of the specialty dolls.

The storm system that developed in the West over the weekend has been blamed in at least 11 deaths, five of them in Texas. But as the storm moved east it wasn't as bad as feared.

A large area of rain was spreading over the Northeast and was expected to gradually move out into the Atlantic and the Canadian Maritimes as the day wore on. Wind was a concern, especially Wednesday morning in Boston. Parts of southeast New England were under a high-wind warning with the potential for wind gusts of up to 60 mph, said Chris Vaccaro, spokesman for the National Weather Service headquarters in Silver Spring, Md.

There was a residual band of snow behind the storm that, as of Wednesday morning, was stretching from western Pennsylvania to West Virginia and into parts of the southeast. It was expected to pivot into parts of the Mid-Atlantic by Wednesday night.

"This is a fairly typical storm for this time of year," Vaccaro said. "Obviously, it's ill-timed because you have a lot of rain and snowfall in areas where people are trying to move around town or fly or drive out of town ... but fortunately, we're at this point going to start seeing a steady improvement in conditions across the Mid-Atlantic and Northeast."

More than 43 million people are to travel over the long holiday weekend, according to AAA. About 39 million of those will be on the roads, while more than 3 million people are expected to filter through airports. The weather could snarl takeoffs and landings at some of the busiest hubs on the East Coast, including New York, Washington, D.C., Philadelphia, Boston and Charlotte, N.C.

Transportation officials advised travelers to check with their airlines and reduce speed on highways. Travel experts suggested airline passengers might be able to have penalty fees waived if they wanted to change their bookings because of the weather.

Weather woes aside, there were some things for travelers to be happy about this year. The Federal Aviation Administration last month lifted restrictions on the use of most personal electronic devices during takeoffs and landings, and some airlines, including American, have already begun allowing passengers to stay powered up from gate to gate.

"I'm always down for Wi-Fi," said a jazzed-up Chris Reichert, a 20-year-old film student at Northwestern University who was headed from Chicago to Baltimore.

His excitement was lost in the generational gap with some older passengers such as Phyllis Dolinko, 79, of Highland Park, Ill., who was bound for LaGuardia.

"I have a cellphone (but) I really wouldn't do that anyway," she said of using in-flight services to browse the Web. "That's discourteous," she sniffed.

Her main weather concern was not that she wouldn't be able to make it to New York City to see her family (her flight was listed on time), but rather that high winds on turkey day might prevent the city from sending up giant balloons for the parade.

The wild weather could leave some of the biggest stars of Thanksgiving on the sidelines, CBS News correspondent Don Dahler reports. Strong wind threatens to take the air right out of the Macy’s Thanksgiving Day Parade balloons.

Every Thanksgiving morning, more than 50 million people tune in to watch New York’s famous parade, but this year the historic procession could be missing some iconic faces. Helium-filled versions of America’s favorite characters annually make the trek through Manhattan.But bad weather is threatening to bring big gusts in the city; the National Weather Service says New York could see winds of up to 37 mph Thursday.

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